Minimally invasive surgical procedures utilizing surgical scopes are desirable because they often provide one or more of the following advantages: reduced blood loss, reduced post-operative patient discomfort, shortened recovery and hospitalization time, smaller incisions, and reduced exposure of internal organs to possible contaminants.
Generally, minimally invasive surgeries utilize scopes, such as laparoscopes, that permit remote visualization of a surgical site within a patient's body while the surgical procedure is being performed. During a laparoscopic procedure, the patient's abdominal or pelvic cavity is accessed through two or more relatively small incisions rather than through a single large incision that is typical in a conventional surgery. Surgical scopes, such as laparoscopes, usually consist in part of a rigid or relatively rigid rod or shaft having an objective lens at one end and an eyepiece and/or integrated visual display at the other. The scope may also be connected to a remote visual display device or a video camera to record surgical procedures.
In laparoscopic surgeries, the abdomen is typically inflated with a gas through the use of an insufflator, to distend the abdominal space by elevating the abdominal wall above the internal organs and thereby create a sufficient working and viewing space for the surgeon. Carbon dioxide is usually used for insufflation, though other suitable gases may also be used. Conventional insufflators are adapted to cycle on and off to maintain a preset and suitable pressure within the patient's body cavity.
The local environment within a patient's abdominal space is generally rather warm and humid, and the use of devices such as harmonic scalpels and other cutting and coagulating devices generate mist, smoke, and other debris that is released into the surgical field and often becomes suspended throughout the expanded abdominal space. Additionally, blood, bodily fluids, pieces of tissue, fat or other bodily material may come in contact with or even attach to the lens. As a result of these conditions, visualization through the scope can be significantly diminished. Typically, the only solution to fogging and debris collection on the lens is removal of the scope from the body cavity and defogging or cleaning the lens by wiping it with a cloth, warming the scope tip, or utilizing another defogging method. The need to remove the scope to defog and remove debris from the lens is inconvenient for the scope operator and the surgeon and can interrupt and undesirably prolong surgical procedures.
As such, some devices have been developed to assist in the improvement of visualization. These devices may provide gas or liquid fluids to the distal end in order to clear the lens area. The cleaning of a laparoscopic lens during a medical procedure, however, requires the ability to control the volume and placement of the fluid. Unplanned and uncontrolled releases of fluid during the procedure, usually small droplets that form drips, are a major visual distraction to the user because they can distort the image either by sliding over the lens or by forming bubbles over the lens.
One approach to preventing drips is to remove the fluid and dry the conduit by pressurized gas or by applying a vacuum to retract fluid from the conduit. In doing so, however, all the fluid must be removed from the conduit. This is difficult to accomplish at a high level of reliability because of fluid surface tension and the high positive pressure or low negative pressure required to absolutely evacuate the conduit.
As such, there remains a need for fluid dispensing control mechanism for cleaning the lens of a laparoscope in situ that prevents the uncontrolled dispensing of the fluid.